SiC, which is superior to Si, etc., in terms of heat resistance, electrical characteristics and the like, has been attracting attention as a new semiconductor material.
Patent Document 1 discloses a surface treatment method for planarizing a SiC substrate. In the surface treatment method, a storage container is heated while the SiC substrate is stored within the storage container under Si vapor pressure. This results in etching the SiC substrate stored within the storage container, to obtain the SiC substrate that is planar at a molecular level.
Patent Document 2 discloses a treatment method for removing a surface modified layer formed on the SiC substrate. Patent Document 2 describes that the surface modified layer is a damage layer of a crystal structure occurred in a step (mechanical processing such as mechanical polishing) of manufacturing the SiC substrate. In this treatment method, the thickness of the surface modified layer is kept equal to or less than 50 nm and the surface modified layer is removed by hydrogen etching.